Hi guys.
I have a need for this following circuit, but it currently uses a automotive relay. I want to make it solid state, and so also quite a bit smaller.

The 12 volt source from the left is controlled by a switch. This is driving a solenoid on the right. The square box. Solenoid has dual coils, one to "open" it (black connection), then the other to "hold" it (green connection).
The circuit creates a pulse for 1-2 seconds to the black wire then leaves the green wire to take over. When the 12 volts is removed from the left, the circuit resets.

Is anyone able to have a look and re-draw it to use a transistor/Mosfet instead please?
Thanks!

Any time ive used a solid state relay it has just had two terminals which were wired in the same manner as a regular relay. Obviously using just a mosfet would require a slight modification to the circuit.

An all in one SSR is going to be the most reliable option and what most EEs would use. If you don't want to do that, you could use a SR flip flop. These are Set and Reset, for your application, reset would be tied it's off state leaving you with just a set. Here's a diagram.

Will a SSR react in the same way as a normal relay?
The circuit I posted uses a cap to hold the pulse for a few seconds.
I would rather use a transistor as it would be smaller than a SSR wouldn't it?
-J

Looking at it now I don't really understand your drawing. Here is a transistor 'switch' attached. L1 symbolizes your solenoid. attach the base of Q9 to anything above 1.5V refrence to GND and current will flow through L1 or whatever you put in L1's place. Q7 may need a small heatsink depending how long they are on with 2.5A running through it, 2.5A is really the max I would go on this. If you use a resistive or capacitive load in place of L1 you can drop D1. The solenoid is inductive so you must keep D1.

Give me some more info and I'll see what I can do. Hope this helps.

__________________

The majority of the people in the world are idiots but, of course, you're not one!

Thanks for that, but yes, I think you might have mis-understood the drawing.
I have 2 coils.
They share a common +12v supply.
Coil 1 is a light draw coil and does not draw much current at all.
Coil 2 is a heavy draw coil at about 2.5 amps.

Thanks for that, but yes, I think you might have mis-understood the drawing.
I have 2 coils.
They share a common +12v supply.
Coil 1 is a light draw coil and does not draw much current at all.
Coil 2 is a heavy draw coil at about 2.5 amps.